POST UTME GREENFIELD UNIVERSITY 2024 Chemistry | Objective

Practice these randomly selected questions to test your readiness.

Question 1
Calculate the s\tandard enthalpy of formation of CO2(g) from the following data: ΔHf(CO2(g)) = -393.5 kJ/mol, ΔHf(C) = 0 kJ/mol, ΔHf(O2(g)) = 0 kJ/mol.
A. -393.5 kJ/mol
B. -394.5 kJ/mol
C. -395.5 kJ/mol
D. -396.5 kJ/mol
Question 2
The rate cons\tant (k) of a first-order reaction is given by the equation: k = Ae^\( -Ea/RT \). If the activation energy (Ea) is 100 kJ/mol, the gas cons\tant (R) is 8.314 J/mol*K, and the temperature (T) is 300 K, calculate the value of k when A = 2.5 x 10^\( -3 \) s^\( -1 \).
A. 1.45 x 10^\( -3 \) s^\( -1 \)
B. 2.45 x 10^\( -3 \) s^\( -1 \)
C. 3.45 x 10^\( -3 \) s^\( -1 \)
D. 4.45 x 10^\( -3 \) s^\( -1 \)
Question 3
A diagram of a titration setup is shown below. What is the purpose of the burette?
A. To measure the volume of the titrant
B. To measure the volume of the analyte
C. To mix the titrant and analyte
D. To measure the pH of the solution
Question 4
A metal (M) reacts with oxygen to form a basic oxide. The reaction is: 4M + 3O2 → 2M2O3. If 2.5 g of M is heated in air, what is the volume of oxygen required at STP?
A. 2.5 L
B. 5.0 L
C. 7.5 L
D. 10.0 L
Question 5
A solution of a weak acid in water is 0.1 M. If the acid is 10% dissociated, what is the concentration of hydrogen ions in the solution?
A. 0.001 M
B. 0.01 M
C. 0.1 M
D. 1 M
Question 6
A solution contains 0.1 M CuSO4 and 0.1 M NaCl. If 10 mL of the solution is titrated with 0.1 M AgNO3, what is the number of moles of Cu2+ ions present in the solution?
A. 0.001 mol
B. 0.005 mol
C. 0.01 mol
D. 0.015 mol
Question 7
A polymer has a molecular weight of 100,000 g/mol and a degree of polymerization of 500. What is the molar mass of the monomer?
A. 150 g/mol
B. 200 g/mol
C. 250 g/mol
D. 300 g/mol
Question 8
The half-life of a radioactive subs\tance is 5 years. If the initial amount of the subs\tance is 100g, how much of the subs\tance will remain after 10 years?
A. 50g
B. 75g
C. 25g
D. 12.5g
Question 9
Determine the pH of a 0.1 M solution of HCl at 25°C. The dissociation cons\tant of HCl is 10^\( -7 \).
A. 1
B. 2
C. 3
D. 4
Question 10
A 25 mL sample of 0.2 M H2SO4 is titrated with 0.1 M NaOH. Calculate the number of moles of NaOH required to reach the equivalence point.
A. 0.005
B. 0.01
C. 0.015
D. 0.02
Question 11
The molecular formula for a hydrocarbon is $C_4H_{10}$. What is the name of the hydrocarbon?
A. Bu\tane
B. Isobu\tane
C. n-Bu\tane
D. Isopen\tane
Question 12
A 25.0 mL sample of 0.100 M NaOH is titrated with 0.100 M HCl. What is the pH of the solution after the reaction is complete?
A. 7
B. 8
C. 9
D. 10
Question 13
A chemical bond is formed when two atoms share one or more pairs of electrons to achieve a stable electronic configuration. What type of bond is formed between two oxygen atoms in a molecule of oxygen gas?
A. Ionic bond
B. Covalent bond
C. Hydrogen bond
D. Van der Waals bond
Question 14
A solution of $NH_4Cl$ in water is a good example of a colloid. What is the name of the colloid?
A. A true solution
B. A colloid
C. A suspension
D. A mixture
Question 15
A 0.1 M solution of HCl is titrated with 0.1 M NaOH. If 25 mL of NaOH is required to reach the equivalence point, what is the pH of the resulting solution?
A. 7
B. 9
C. 10
D. 12

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